Visualization of FC72 confined nucleate boiling

This paper presents a new visualization study for confined and unconfined boiling of FC72 at atmospheric pressure and low and moderate heat fluxes (⩽40 kW/m2) on a downward facing disc placed at 0.2, 0.5, 1 and 13 mm distance from the base of a boiling chamber. The results show that boiling for s = 0.2 and 0.5 mm can be considered enhanced compared with s = 1 and 13 mm. Still photographs of the boiling phenomenon showed the coexistence of isolated and coalesced bubbles for s ⩾ 0.5 mm and the predominance of deformed coalesced bubbles for s = 0.2 and 0.5 mm.